Given the fact that over 4 million infants are delivered in hospitals every year, the provision of obstetric care is a critical part of the health care system. Although the optimal supply of obstetric beds in a given geographic region is unknown, obstetric unit closures are a common occurrence. Prior work from California hospitals has shown that, when a hospital is eliminating certain service areas, obstetric care was the most common service area to be eliminated. There are many factors contributing to these closures including increasing malpractice premiums, financial losses and fear of litigation. Additionally, these closures often disproportionately affect minority and low-income communities. Given the large number of women annually that receive obstetric care, it is plausible that obstetric closures can have a significant impact on the health outcomes of communities. However, the impact of these closures on the health of the surrounding population is not well described. Our group has previously investigated Philadelphia, where 9 of 19 obstetric units closed between 1995 and 2005. This study showed that, compared to a pre-closure period of 1995-1996, this reduction in obstetric bed supply resulted in an initial increase in neonatal and all fetal mortality, an initial and late decline in the number of deliveries via Cesarean section. This observation raises multiple questions about the impact of even a small number of obstetric unit closures on short-term and long-term outcomes of obstetric care. There are no studies of the impact of these obstetric closures on the costs, outcomes, and quality of care for both (a) patients who reside close to the closed obstetric unit and (b) patients within the larger geographic area, nor are there studies to understand how characteristics of the health care market and the hospitals that close modify these associations. Our findings in Philadelphia and a study demonstrating increased prevalence in babies with low birth weight in rural Missouri after discontinuation of obstetric services, highlight the need to have specific studies dedicated to evaluating maternal and neonatal outcomes after obstetric unit closures. If in fact obstetric unit closures adversely impacts both the immediate and surrounding communities, there is the potential to create significant systems changes in communities when preparing for a closure to combat these adverse affects. Prior to providing guidance to hospital administrators, obstetrical leaders, and government officials suggesting significant resource utilization to combat obstetric unit closure affects, rigorous research is needed to study the effect of closures on maternal and neonatal outcomes. Studying the impact of closing a service that impacts over 4 million women and their families each year is of great societal importance. . PUBLIC HEALTH RELEVANCE: Although over 4 million infants delivering in the United States every year, the reduction of obstetric services through the closure of obstetric units is a common occurrence. This application will investigate the impact of obstetric unit closures on the pregnancy outcomes of both the larger community and the smaller community serviced by the closed obstetric unit. Improved understanding of the impact of such service reductions in the obstetric market will result in more efficient use of health care services and optimize the value of health care dollars spent on obstetric care.